Contiforce SM front causing instability
 

I have just had a Contiforce SM tyre fitted to the front wheel in place of the Ageing and worn out Pirelli but now the bike weaves very badly at 70mph +. Its most prominent after exiting a bend as the bike comes back upright its weaves until I back off.

Previously I had the front Pirelli with a rear Contiforce SM and experienced no weaving at all at any speeds.

I am running the tyres at 30/30 psi.

Anybody else experienced issues with these tyres and overcome them?

Pauli you are running too much pressure on a brand new tyre, bring it down to 28psi until the tyre is road worn / bedded in and then inflate gradually up to 30 if that is how you like it.

Why Capt ?

28psi, thats nearly flat!! i run my XTR tyres both at 33-35psi. Nevery had any instablity problems at speed be it new or old tyres (well unless you call sliding the rear over cow poo stablity problems):icon_blackeye:

the owners manual specifes 29-30 front and 32-33 rear as standard.

(suprisingly low i thought)

Because a Supermoto is not a Sportsbike and not a lot of people, (especially tyre mechanics) understand that these bikes are a lot different in traction and torque, the frame design requires that the better stability and handling are achieved with 28-29-30 psi depending on rider's weight. Big lads might need to inflate up to 33psi.

1. You are a healthy big lad
2. You are running semi-knobblies and your bike is not a 17in wheeled supermoto.
3. Your fork is longer than the X

Sorry, my question must have been phrased badly.

Why would you start at 28 and increase as the tyre wears ?

This is not low at all because as the Capt explained the XTX is not a sport bike. I never inflate my tyres over 29 psi. I tried those tyres some years ago and did not have the problems you mention. Could you describe the "shaking" in more detail ?

The best way I can describe is that it feels like the whole bike is pitching from side to side and will keep on doing so until I back off the throttle. It only happens at 70+ and not at all below that no matter how I try and provoke it.

As I said in the original post it seems worse when straightening up after a bend, but also this evening I had a quite nasty one when crossing a white line in the centre of the road at around 75mph.

I will go and get an accurate pressure gauge as I'm using one attached to a cheap Halfords pump at the moment - just in case its reading badly.